We went to Alaska this past summer and we would not hesitate to do it solo. Buy a copy of The Milepost. It has lots of information on campgrounds, attractions, etc. We found the roads to be generally good, with a few bad spots with frost heaves, almost always some construction because their window to fix the roads is very narrow. Weather rules activities in Alaska. The key is to slow down. Your May-Aug timeframe sounds good. Don't rush it; this is beautiful country, lots of wildlife, and natural scenic beauty. Even though this is vast terrain, we found ourselves running into the same people on the road, at rest stops, campgrounds, etc.
We made reservations in the bigger cities (Fairbanks & Anchorage) and the Kenai Peninsula; otherwise, we just took our chances and had no problems. There is also opportunity to drycamp if that's your cup of tea.
We started out with 4 couples traveling loosely together; we were by ourselves most of the time because we really liked the slow pace we could set ourselves.
As usual, use the good judgement and common sense you would use traveling in the lower 48.